This invention relates to bindings for water skis, and, more particularly, to a device for locking a water ski binding in a desired position.
The invention is an improvement over the cam latch which is described in U.S. Pat. No. 4,494,939. As described in that patent, water ski bindings commonly include wing nuts for clamping the heel cup of the binding against the ski so that the heel cup is maintained in the desired position. The wing nuts are threadedly engaged with studs which extend upwardly from the ski through slots in the heel cup.
U.S. Pat. No. 4,494,939 describes a cam latch which is used in place of the wing nuts. The cam latch is pivotally secured to the stud for pivoting about an axis which extends perpendicularly to the stud. The bottom of the cam latch is elliptically shaped and eccentrically mounted with respect to the pivot axis. The elliptical portion of the cam engages one of a plurality of arcuate detents in the heel cup, and as the cam latch is rotated over center, the cam forces the detent and the heel cup forwardly. The forward movement of the heel cup can cause discomfort to the foot of the skier. Also, the device cannot easily be adjusted to compensate for wear.
The invention provides a two-part locking device which provides a downward clamping force on the heel cup and which can be moved quickly and easily from a locking position to an unlocked position by rotating one of the parts less than one-half of a turn. The stud extends through both parts of the lock, and the lower part of the lock rides on the heel cup and engages the slot in the heel cup so that it cannot rotate relative to the heel cup. The upper part of the lock is positioned between the lower part and the head of the stud. Both lock parts are provided with camming ramps which are engageable with each other, each camming ramp extending spirally around the stud for about 180.degree.. The bottom surface of the bottom part is serrated or roughened and engages a similarly serrated or roughened surface on the heel cup. When the upper part is rotated about the axis of the stud, the camming ramps force the bottom part downwardly to clamp the heel cup against the ski. The lock can be moved between the unlocked and locking positions merely by rotating the upper part of the lock less than one half of a turn, and the locking force is exerted downwardly on the heel cup rather than downwardly and forwardly. As a result, the heel cup is not moved forwardly from the position which is initially selected. The interengaged serrated surfaces of the bottom part of the lock and the heel cup decrease the possibility that the heel cup will slide relative to the ski and provide finer increments between adjacent locking positions than do any of the prior art devices previously referred to. Further, the clamping force can be adjusted and fine tuned merely by rotating the stud.